Peloponnesian War

The Peloponnesian War was an ancient Greek war fought by the Athenian-led Delian League against the Spartan-led Peloponnesian League from 431 to 421 BC (the Archidamian War), from 415 to 413 BC (the Sicilian Expedition), and from 413 to 404 BC (the Decelean/Ionian War). The war was both a struggle between democratic Athens and monarchial Sparta for hegemony over the Greek world as well as a clash between the warlike Dorians (Spartans) and the philosophical Ionians (Athenians). The war resulted in the utter devastation of Greece, the transformation of Greek warfare from formal and limited conflicts into an all-out struggle between city-states, the destruction of whole cities, and the dramatic end of the Golden Age of Greece.

Background
The origins of the Peloponnesian War lay in the growing wealth and power of Athens and the fear and resentment that this engendered in other Greek city-states. After the defeat of the Persian invasion of Greece in 480-479 BC, Athens assumed leadership of an alliance of city-states around the Aegean, the Delian League. The original purpose of the league was to fight the invasion of the Persians, but it turned into an informal Athenian empire with the other league members providing troops and tribute for Athens to use as it wished. Cities that rebelled were ruthlessly crushed by Athenian military action. The wealth extracted from the league during this period underpinned the Golden Age of Athens under the leadership of Pericles, and the Athenian statesman believed that the interests of the city lay in developing trade around the Mediterranean. The Spartans, traditionally acknowledged as the leading military power in Greece, were affronted by the rise of Athens and turned the Peloponnesian League of city-states which they led into a counter-balance to Athenian power.

War
The fragmentation of the Greek world into independent city-states presented many opportunities for conflict - disputes over allegiance, territorial boundaries, and affronts to honor. Around 460 BC, a clutch of such issues brought a drift to war. Relations between Athens and Sparta were embittered by an exchange of insults over the Athenians' role in helping the Spartans suppress an uprising of helots (serfs or slaves). The city-state of Megara revolted against its overlord, Corinth, a member of the Spartan-led Peloponnesian League; Athens backed Megara. Thebes aspired to leadership of the cities of Boeotia, a role denied it by Athens; the Spartans backed Theban aspirations. After a series of skirmishes and campaigns, the Athenians and Spartans agreed a Thirty Years' Peace in 445 BC. It lasted less than half that time.

In 435 BC, Corinth faced a revolt by its colony Corcyra (Corfu). The Athenians backed the Corcyrians and sent a force of triremes to prevent the Corinthians from re-imposing their rule. Corinth appealed to the Peloponnesian League for support and in 432 BC Sparta declared war on Athens. Fighting began the following year. Pericles devised a strategy based upon the naval power of Athens and the Delian League allies. Withdrawing within the walls of their city, the Athenians would survive sustained by supplies brought in by sea, while using their fleet to raid the shipping and coasts of the Peloponnesian League states. Five times the Spartans rampaged through the territory around Athens, but without decisive effect. The Athenians made good use of their naval strength by establishing a base at the town of Pylos on the Peloponnesian coast, from which they raided Spartan territory and encouraged revolt among the Spartan helots. When the Spartans attacked the Pylos garrison in 425 BC they were outmaneuvered by Athenian sea and land forces and defeated. The Athenians, on the other hand, were beaten badly by Sparta's allies, the Theban-led Boeotians, at Delium in 424 BC, a reminder of their weakness on land. The warfare was characterized by the similarity between the opposing sides, which fought with essentially the same equipment and tactics. The core of the rival armies was the heavy infantry hoplite, a citizen-soldier fighting in a tight-knit formation, the phalanx. The hoplites were supported by large numbers of skirmishers, the peltasts, men of lower social status who used missile weapons - bows, slingshots, and javelins. Once on enemy territory, any army would plunder and lay waste at will. Campaigns were short because part-time soldiers needed to return to their farms. A fleet was far more expensive to maintain than an army, and made heavy demands on manpower. A trireme required a crew of 200, most of them experienced oarsmen, although they were typically lower class citizens rather than hoplites. The naval dominance of Athens depended on its superior financial resources and its skilled population of seafarers and boat-builders. As on land, there were no adequate supply arrangements, triremes beaching regularly to forage or buy food from coastal towns. Sea battles were ramming contests decided by dexterity of maneuver.

Athens defeated
The first round of the Peloponnesian War came to an end in 422 BC, after the chief war leaders on the opposing sides, the Spartan general Brasidas and the Athenian demagogue Cleon, were both killed while campaigning in Thrace. Despite a resultant peace agreement made the following year, skirmishes continued uninterrupted and a full-scale battle was fought at Mantinea, north of Sparta, in 418 BC - a Spartan victory that confirmed the supremacy of their hoplites. At this point the Athenians extended the war into a new theater, with disastrous consequences. In 415 BC, they sent an expedition to Sicily, seeking to defeat the dominant city of Syracuse and bring the island into their empire. Supported by a relatively small Spartan force under Gylippus, the Syracusans resisted an Athenian siege for two years. Athens poured in more troops, but by 413 BC it was they who were trapped, their fleet blockaded in Syracuse harbor. After a failed breakout attempt ended in the destruction of the majority of their warships, the Athenians vainly tried to escape overland. Harassed by cavalry and light troops with bows and javelins, the remnants of the expeditionary force surrendered, ending their lives as slaves laboring in Sicilian stone quarries.

This comprehensive Athenian disaster encouraged the Spartans. They made an alliance with Persia, which provided funding to build a fleet that could compete for naval supremacy. Athens was in trouble, riven by political disputes and unable to make good for loss of experienced oarsmen and sailors at Syracuse. The Athenians achieved a last naval victory at the Battle of Argusinae in 406 BC, but Sparta was more readily able to make good its heavy losses than Athens its relatively light number. Athens was utterly dependent for food supplies on food imported from the Black Sea and the war came finally to focus on Spartan efforts to sever that lifeline by winning control of the Hellespont. Under Lysander, the Spartan fleet seized the straits and, at the Battle of Aegospotami, crushed an Athenian fleet sent to win them back. Athens surrendered in 404 BC.

Aftermath
The Spartan victory in the Peloponnesian War did not bring peace or unity to the Greek city-states. Weakened by civil strife, they fell under the rule of Macedonia. Ten years after the end of the war, a new conflict broke out. The Corinthian War set Sparta against Corinth, Athens, Thebes, and Argos. These allies were dependent upon the support of Persia, which re-imposed its rule on the Ionian cities of Anatolia.

The Corinthian War ended in a compromise in 387 BC. Thebes aspired to leadership in its own region, Boeotia, but this was resisted by Sparta. Inspired by their general Epaminondas, the Thebans defeated the Spartans at Leuctra in 371 BC. In reaction to the threat of Theban hegemony, Athens aligned itself with Sparta. Epaminondas scored another victory over Sparta, Athens, and their allies at Mantinea in 362 BC, but he was killed in the battle, preventing Thebes from profiting from its triumph.

The Greek city-states were exhausted. When Philip II of Macedon invaded Greece in 338 BC, he defeated the combined armies of Athens and Thebes and united the country by force, organizing the city-states into the Macedonian-led League of Corinth.